Mathematical understanding of the multi-species biological networks underpinning rabies transmission

"Zero by 30" is a global strategic plan to prevent human deaths from dog-transmitted rabies by 2030. We are a long way from achieving this goal as recent estimates suggest that approximately 59,000 [95% Confidence Interval (CI): 25,000-159,200] human rabies deaths occur annually globally. As well as their impact on human health and economics, rabies outbreaks can also be devastating for wild animal species. Previous studies from Tanzania suggest that although wild carnivores contribute to the reservoir of rabies infection, domestic dogs are the only population necessary for maintenance of infection. However, recent results from areas of southern Tanzania where levels of rabies vaccination amongst domestic dogs are high, may suggest the presence of an alternative maintenance host in this region.
The aim of this study is to use mathematical and statistical methods to improve our understanding of the biological contact networks underpinning the multi-species transmission of rabies virus. To achieve this, novel, multi-species deterministic and stochastic models will be developed to represent rabies transmission both within and between species. These will initially be parameterised using new data collected from 8 regions of southern Tanzania which incorporate details of rabies cases in domestic and wild animals from 2007-2017. (Data provided by Dr Katie Hampson and Professor Sarah Cleaveland, Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow). Maximum likelihood methods and Bayesian Markov Chain Monte Carlo (MCMC) methods will be used for parameter estimation using the information from the data set within the model structure. The best fit model will be used to identify which species or combinations of species are acting as maintenance hosts within a region and which features allow them to act as maintenance hosts. In addition, the model will be used to explore the likelihood of rabies extinction within a region and the associated timescale and potential for re-emergence. Models will initially be developed to reflect a southern Tanzanian setting but then applied to other areas of Africa where rabies is endemic.